A simple electrochemical route to metallic phase trilayer MoS₂: evaluation as electrocatalysts and supercapacitors

Abstract

The development of a simple, scalable and reproducible technique for the synthesis of two-dimensional metallic phase MoS2nanosheets is of paramount importance in the field of catalysis and energy storage devices.

Metallic MoS2 for High Performance Energy Storage and Energy Conversion

“…Semiconducting MoS 2 exhibits characteristic optical peaks due to its photoluminescence energy of ≈1.9 eV, consistent with its bandgap energy . As the ultraviolet–visible spectroscopy spectra shown in Figure a, the semiconducting phase (red curve, solution exfoliated) owns two notable peaks at 604 and 667 nm, related to the direct‐gap transition . By contrast, no visible peaks appeared at 604 and 667 nm for metallic MoS 2 , as the bandgap energy is different for metallic MoS 2 compared to the semiconducting phase of MoS 2 (black curve, electrochemically exfoliated in Figure a).…”

“…The metallic MoS 2 and semiconducting MoS 2 can also be distinguished by prominent differences in their appearance. The dispersion of semiconducting phase of MoS 2 is dark yellow or green, whereas the color of the metallic phase is dark grey (inset image in Figure a). Figure b is another optical absorption spectra for metallic and semiconducting phase MoS 2 .…”

“…a) Optical absorption spectrum of MoS 2 dispersion in the mixture of water and isopropanol (1:1). Reproduced with permission . Copyright 2017, Royal Society of Chemistry.…”

Electrochemical Exfoliation of MoS2 Crystal for Hydrogen Electrogeneration

“…For comparison polarization curves and corresponding Tafel plots of bare glassy carbon (GC) electrode and Pt/C modified electrode are also shown in Figure 5. [32] This is likelyd ue to the presence of oxides on the material surface as well as the predominant 2H semiconducting characteristics as evidencedb yX PS measurements. [32] This is likelyd ue to the presence of oxides on the material surface as well as the predominant 2H semiconducting characteristics as evidencedb yX PS measurements.…”

“…[23] Intercalation/exfoliation with Li-based organic solvents is certainly more efficient with large amount of single or few-layer thick nanosheets obtained. Extremelyp owerful when appliedf or the exfoliation of graphite to obtain graphene, [27,28] is recently being considered also for the exfoliation of other layered materials such as Bi 2 Se 3 ,B i 2 Te 3 , [29] black phos-phorous [30] andM oS 2 , [31,32] showingp otentiality as universal procedure for fast and efficient top-down method. [25,26] Another procedure which demonstrated excellent resultsi n terms of quality of the exfoliated material, high yields,s imple operations and lower environmental impact is represented by the electrochemical-assisted exfoliation.…”